DEVICE AND METHOD FOR CONTROLLING ENDPOINT OF USB DEVICE HAVING NO FIXED OBJECT APPLICATION

摘要

PURPOSE: A device and a method for controlling an endpoint of a USB(Universal Serial Bus) device having no fixed object application are provided to improve overall performance by minimizing NAK(Negative Acknowledge) occurrence during data reception by making the endpoint having many throughout have more buffers, and making the endpoint having fewer throughout have fewer buffers. CONSTITUTION: A programmable endpoint FIFO(First Input First Output)(722) s assigned to each endpoint. To minimize the NAK occurrence, an endpoint buffer controller(728) resets the FIFO buffer to each endpoint by counting the NAK ratio of each endpoint in a predetermined period while transmitting/receiving a packet with a host through a serial interface engine. The endpoint buffer controller is equipped with a buffer status checker(810), an M-bit period controllable timer(840) generating a NAK counting reset signal for each period, an M-bit NAK counter(820) counting the NAK generated in each endpoint within the period and passing over a NAK counting value of each endpoint if the reset signal is generated from the timer, and a FIFO pointer controller(830), and a NAK threshold controller(850).